"Initial results from these two detailed and rigorous audits showed the plant at Scunthorpe as ‘Good’ and the plant at Llangefni as ‘Generally Satisfactory’.

The FSA will publish the completed audits in due course.”

Ranjit Singh, CEO of 2 Sisters Food Group, said: “We welcomed these audits and we are pleased the FSA has worked with typical rigor and thoroughness.

“We are satisfied with their findings which show that no legislative compliance issues were raised.

“However, we must not be complacent. We operate our business in an environment of continual improvement and we will be carrying on with that to ensure we produce first-class British products for all of our customers.

“We will continue to be at the forefront of our sector by investing in our sites and leading from the front in tackling key challenges to our industry like campylobacter.”

Last week, Health Secretary Jeremy Hunt called for the probe after reports in the Guardian made claims that feathers, guts and offal were piling up on the factory floor for hours, leading to the threat of contamination with the potentially deadly campylobacter bug.

2 Sisters is the UK’s largest poultry company supplying major supermarket chains and strongly denied the allegations.

Following the publication of the allegations this week, three of the biggest supermarkets – Tesco, Sainsbury’s and Marks & Spencer – launched investigations into their chicken supplies.